This invention relates to a corpuscular beam apparatus in general and more particularly to improved object adjustment apparatus for such an apparatus.
Typically the object adjustment device in a corpuscular beam apparatus such as an electron microscope, generally termed the object stage contains only mechanical elements for adjusting the object carrier in a plane perpendicular to the axis of the equipment and to the electron beam. That is the equipment e.g. electron microscope will have an equipment axis upon which the electron beam is provided. For purposes of this disclosure this can be thought of as an axis in the vertical direction. (For purposes of simplicity the discussion herein will be in terms of an electron microscope. It should be recognized, however, that the present invention may be used with other types of corpuscular beam apparatus such as electron beam diffraction apparatus, ion beam microscopes, or X-ray microanalysis (microsonde).) The object to be observed in the microscope is contained in an object carrier. The object carrier is then attached to an object stage which is movable in a plane perpendicular to the equipment axis, that is, an horizontal plane. For some purposes it is desired, in addition to being able to laterally move the object to also rotate the object about an axis which is different than the axis of the equipment. In particular, it is sometimes desirable to rotate the object about an axis which is perpendicular to the axis of the equipment. Assuming the equipment axis is in vertical such another axis would lie in a horizontal plane. Another type of axis should also be defined. This is the object axis passing through the object which is perpendicular to the plane of the object. With the object carrier lying in an horizontal plane this axis through the object will coincide with the equipment axis. However, if the object plane is tilted from the horizontal on an axis lying in the horizontal plane, this object axis no longer coincides with the equipment axis but is now at an angle thereto. The two axes will intersect at the point in the object being observed. In some cases it may also be desirable to rotate a tilted object carrier about the axis through the object. In the present invention when referring to rotation both of these types of rotation are included, i.e., that corresponding to tilting and that corresponding to rotation about the tilted object axes.
An adjustment device which provides some of these capabilities is described in German Offenlegungsschrift 1,539,063. This device, however, provides axes of rotation which shift when the object carrier is linearly displaced. Thus the axis about which rotation occurs does not intersect the axis of the equipment. The result is that the point of the object which is being viewed will wander in the field of view with rotation or tilting. Although operation in which the axis of rotation will intersect the equipment axis for any lateral position can be achieved in object adjustment devices in which the specimen is laterally introduced, these devices are inferior, in regard to accuracy and stability, to the type wherein the object stage is inserted perpendicular to the equipment axis. This results from the smallness of the available space.
Thus, there is need for an adjustment apparatus for adjusting the object in an electron microscope or the like which permits lateral adjustment along with allowing rotational adjustment about ab axis which alsways intersects the equipment axis.